Election officials had initially said that turnout had passed 70 per cent two hours before the voting booths closed, and had been above 80 per cent in some areas. But by later on Sunday evening, it became apparent that the electorate was even more enthusiastic than expected.

ISIE electoral commission secretary-general Boubaker Bethabet said more than 90 per cent of some 4.1 million citizens who registered ahead of the poll had cast their votes on Sunday - at least half of all eligible voters.

No figures were available for the other 3.1 million voters who did not register but also had the right to vote.

Barack Obama congratulated Tunisians on the vote, which he described as "an important step forward."

"The United States reaffirms its commitment to the Tunisian people as they move toward a democratic future that offers dignity, justice, freedom of expression, and greater economic opportunity for all," he said in a statement.

Ennahda, the Islamist Party, has been predicted to emerge as the strongest single party when the count is declared on Tuesday, with as much as 40 per cent of the vote.

But in a sign of how divisive its message of putting an end to half a century of nationalist, aggressively secular rule has been, its leader Rached Ghannouchi was jeered and heckled after he cast his ballot in Tunis, with opponents shouting out that he was a "terrorist".

Mr Ghannouchi lived in exile in London for 22 years until the overthrow of President Zine al-Abedine Ben Ali in January.

The mood was however overall cheerful and determined. When Mr Ghannouchi, who was followed by journalists, attempted to head straight into the polling booth he was stopped by fellow voters. "The queue, the queue – democracy starts here," they shouted to him, forcing him to take his place at the end of a line that stretched back half a mile.

The vote will appoint a president and an interim parliament that will govern for a year and decide a new constitution. As none of the parties will win an overall majority, the country is likely to head to a further period of profound uncertainty.

The range of parties on offer demonstrates the desire for change of most Tunisians but also the difficulty the political system will have in constructing clear political lines in the coming year.

There were 110 parties to choose from as well as independents, represented by more than 11,000 candidates for the 218-seat parliament. Each list has to comprise 50 per cent women, in an attempt to ward off fears that the revolution will end Tunisia's reputation as the Arab world's most progressive state.

Marwen Hamadan, a 23-year-old architecture student voting in Cite al-Riadh Primary School in an upper-middle class district of Tunis, said he had marked his ballot for the Communists, partly out of concern for the strength of Ennahda.

"I don't want to live with Islamic ideology," he said. "Tunisia is a diverse civilisation, it is a mix of political and religious opinions. (Ennahda) will be a dictatorship in another form – before it was a political one and I worry that Ennadha would impose a religious one."

Mohammed Ammar, 46, communications consultant, was sanguine about the prospect of an Ennahda victory.

"It will be Ennahda," he said. "I think if everything goes well the vote will represent Tunisia."

Since the fall of Ben Ali, who is now in exile in Saudi Arabia, hopes for a peaceful transition to a technocratic, consensus-based rule have been dashed by growing economic problems, accusations of corruption, and claims that the former president's circle have been allowed to return to the political process in a new guise.

Meanwhile, radical Salafi Muslims have staged repeated protests, in one case attacking a television station that had shown a "blasphemous" film and the home of the station's director.

But among those who voted yesterday were the family of Mohammed Bouazizi, a fruit-and-vegetable seller who killed himself by setting himself on fire last December after having his cart confiscated. That event turned into nationwide protests and then a movement that toppled his own president and spread across the region.

"All night, I thought of my brother who was the source of the great event we are experiencing today and thanks to whom Tunisians are voting freely," his brother Salem, a 31-year-old carpenter, said.

TUNIS (Reuters) - Moderate Islamists claimed victory on Monday in Tunisia's first democratic election, sending a message to other states in the region that long-sidelined Islamists are challenging for power after the "Arab Spring."

Official results have not been announced, but the Ennahda party said its workers had tallied the results posted at polling stations after Sunday's vote, the first since the uprisings which began in Tunisia and spread through the region.

"The first confirmed results show that Ennahda has obtained first place," campaign manager Abdelhamid Jlazzi said outside party headquarters in the center of the Tunisian capital.

As he spoke, a crowd of more than 300 in the street shouted "Allahu Akbar!" or "God is great!" Other people started singing the Tunisian national anthem.

Mindful that some people in Tunisia and elsewhere see the resurgence of Islamists as a threat to modern, liberal values, party officials said they were prepared to form an alliance with two secularist parties, Congress for the Republic and Ettakatol.

"We will spare no effort to create a stable political alliance ... We reassure the investors and international economic partners," Jlazzi said.

Sunday's vote was for an assembly which will sit for one year to draft a new constitution. It will also appoint a new interim president and government to run the country until fresh elections late next year or early in 2013.

The voting system has built-in checks and balances which make it nearly impossible for any one party to have a majority, compelling Ennahda to seek alliances with secularist parties, which will dilute its influence.

"This is an historic moment," said Zeinab Omri, a young woman in a hijab, or Islamic head scarf, who was outside the Ennahda headquarters when party officials claimed victory.

"No one can doubt this result. This result shows very clearly that the Tunisian people is a people attached to its Islamic identity," she said.

REVOLUTION INSPIRED UPRISINGS

Tunisia became the birthplace of the "Arab Spring" when Mohamed Bouazizi, a vegetable seller in a provincial town, set fire to himself in protest at poverty and government repression.

The revolution in Tunisia, a former French colony, in turn inspired uprisings which forced out entrenched leaders in Egypt and Libya, and convulsed Yemen and Syria -- re-shaping the political landscape of the Middle East.

Ennahda is led by Rachid Ghannouchi, forced into exile in Britain for 22 years because of harassment by Ben Ali's police.

A softly spoken scholar, he dresses in suits and open-necked shirts while his wife and daughter wear the hijab.

Ghannouchi is at pains to stress his party will not enforce any code of morality on Tunisian society, or the millions of Western tourists who holiday on its beaches.

He models his approach on the moderate Islamism of Turkish Prime Minister Tayyip Erdogan.
The party's rise has been met with ambivalence by some people in Tunisia. The country's strong secularist traditions go back to the first post-independence president, Habiba Bourguiba, who called the hijab an "odious rag."

Outside the offices of the commission which organized the election, about 50 people staged a sit-in demanding an investigation into what they said were irregularities committed by Ennahda. Election officials said any problems were minor.

"I really feel a lot of fear and concern after this result," said Meriam Othmani, a 28-year-old journalist. "Women's rights will be eroded," she said. "Also, you'll see the return of dictatorship once Ennahda achieves a majority in the constituent assembly."